Lets say I want to create a cookie for a user. Would simply generating a 1024 bit string by using /dev/urandom, and checking if it already exists (looping until I get a unique one) suffice?
Or should ...

I always hear that C rand() is not secure, but what how many calls would you need to know in order to predict the next value (or at least cut down the possibilities)? Would they have to be sequential? ...

There are some pseudo-random-number generators in PHP: rand(), srand(), mt_rand(), mt_srand(). You can look at their code here.
I understand those functions are insecure, but how insecure are they?
...

A security conscious friend of mine was attempting to generate entropy using random dice rolls to generate a random password, and I became curious about the security of random number generators and ...

Since the Linux RNG which provides /dev/random (and by extension /dev/urandom) is seeded by "mouse and keyboard activity, disk I/O operations, and specific interrupts" (source, PDF) and since virtual ...

Which mobile OS's provide a primitive to generate crypto-quality randomness that applications can use?
On desktop systems, these features are pervasive. Unix provides /dev/urandom. Windows provides ...

Ever since I've been making sites that require a user to log in with a username and password I've always kept the passwords somewhat secure by storing them in my database hashed with a salt phrase. ...

When generating a password, should it be "truly random" or should I make it a little less random by enforcing some rules?
If a password is generated at random, it could come out all-lowercase letters ...

I couldn't find the answer for the reason anywhere, even the wiki page doesn't explain it. This seems like using a PRNG for seeding an another PRNG. The first one (/dev/random) may itself be seeded by ...

If I have a good random number generator that gives me a byte of data at a time, and I want to extract a random decimal digit of 0 to 9 from that byte stream, what is the correct way to do that?
At ...

When setting up a server, what configuration changes do I need to make sure that all of the software uses /dev/urandom instead of /dev/random?
Some servers don't have much entropy in the entropy pool ...

I am creating an application which runs on a mobile node with Ubuntu, which does not generate enough entropy bytes to the /dev/random, and does not always stay connected on the Internet to use typical ...

Suppose one wants to setup a cryptographic protocol in which 2 parties communicate using an encryption scheme that produces encrypted messages indistinguishable from random data (the desired property) ...

I've created a few encrypted devices with LUKS and cryptsetup on Linux and am pretty comfortable with disk encryption in this regard.
I've seen it mentioned in many different places that when setting ...

When generating randomness using SecureRandom in Android, I want to select /dev/random or /dev/urandom as the seed source. It can be done in java.security file on Linux and Windows systems but there's ...